Impacts of common variants in ALDH2 on coronary artery disease patients

Ferroptosis and cardiovascular disease: role of free radical-induced lipid peroxidation

Cardiovascular disease (CVD), including heart attack, stroke, heart failure, arrhythmia, and other congenital heart diseases remain the leading cause of morbidity and mortality worldwide. The leading cause of deaths in CVD is attributed to myocardial infarction due to the rupture of atherosclerotic plaque. Atherosclerosis refers a condition when restricted or even blockage of blood flow occurs due to the narrowing of blood vessels as a result of the buildup of plaques composed of oxidized lipids. It is well-established that free radical oxidation of polyunsaturated fatty acids (PUFAs) in lipoproteins or cell membranes, termed lipid peroxidation (LPO), plays a significant role in atherosclerosis. LPO products are involved in immune responses and cell deaths in this process, in which previous evidence supports the role of programmed cell death (apoptosis) and necrosis. Ferroptosis is a newly identified form of regulated cell death characterized by the iron-dependent accumulation of lipid hydroperoxides to lethal levels, which exhibits distinct features from apoptosis, necrosis and autophagy in morphology, biochemistry and genetics. Emerging evidence appears to demonstrate that ferroptosis is also involved in CVD. In this review, we summarize the recent progress on ferroptosis in CVD and atherosclerosis, highlighting the role of free radical LPO. The evidence underlying the ferroptosis and challenges in the field will also be critically discussed.

Association between the incidence of hypertension and alcohol consumption pattern and the alcohol flushing response: A 12-year follow-up study

BACKGROUND

Alcohol consumption is associated with hypertension, and this association depends on the alcohol consumption pattern and alcohol flushing response. In this 12-year follow-up study, we investigated the relationship between the alcohol consumption pattern and incidence of hypertension in the Korean population.

METHODS

We analyzed 1,366 Korean participants in the Ansung-Ansan cohort study without hypertension at baseline. The subjects were classified into four alcohol consumption patterns: never-drinking, light alcohol consumption, moderate alcohol consumption, and heavy alcohol consumption, and as flushers or non-flushers in response to alcohol.

RESULTS

In flushers, moderate and heavy alcohol consumption patterns increased the risk of incident hypertension compared with never-drinkers [moderate: HR 1.811 (95% CI 1.084-3.028); heavy: HR 2.494 (95% CI 1.185-5.247)], but non-flushers were not associated with increased risk of incident hypertension according to the alcohol consumption pattern. In addition, a heavy alcohol consumption pattern increased the risk of hypertension among flushers compared with non-flushers [HR 2.232 (95% CI 1.054-4.728)].

CONCLUSION

In this 12-year follow-up study, we observed that moderate and heavy alcohol consumption was associated with an increased risk of hypertension in flushers. Especially, a heavy alcohol consumption pattern in flushers markedly increased the risk of hypertension.

Acetaldehyde Dehydrogenase 2 rs671 Polymorphism Affects Hypertension Susceptibility and Lipid Profiles in a Chinese Population

Previous studies revealed that the rs671 polymorphism in the acetaldehyde dehydrogenase 2 (ALDH2) genes is correlated with alcohol consumption in Japanese population. The ALDH2 gene variants and drinking are associated with hypertension and dyslipidemia. However, it remains unclear whether there might be potent relationships among ALDH2 rs671 polymorphism, alcohol consumption, hypertension, and dyslipidemia in Shandong population. A total of 467 male volunteers from Shandong area were enrolled in this study. The ALDH2 rs671 polymorphism was genotyped using polymerase chain reaction-restriction fragment length polymorphism. The concentrations of total cholesterol (TC), triglycerides, low-density lipoprotein, and high-density lipoprotein (HDL) in serum were measured using commercial kits. SPSS 23.0 was used for statistical analysis. The significance of differences between subgroups was determined using chi-square test, and multiple comparisons were performed with the least-significant difference method. The ALDH2 variant frequencies were 80.5% with GG, 17.1% with GA, and 2.4% with AA. The ALDH2 genotypes had significant correlations with alcohol consumption (p = 0.001), whereas the GA genotype was associated with a decreased risk of alcohol consumption (odds ratio = 0.27; 95% confidence interval = 0.130-0.539; p = 0.001). The ALDH2 genotypes frequencies and drinking habits were significantly different between hypertension and healthy individuals (p = 0.034; p = 0.044). The ALDH2 GG genotype individuals have high average lipids levels, and the proportion of TC disorder among GG individuals was higher than that of GA individuals (p = 0.006). Individuals who had drinking habits have a high average lipids levels; especially average TC levels (p = 0.048), and had high proportions of dyslipidemia (TC and HDL; p = 0.016 and p = 0.033, respectively). The frequencies of ALDH2 variants were evaluated according to the Hardy-Weinberg equilibrium among enrolled population. Our study suggested that the individuals with ALDH2 rs671 GA genotype were less prone to developing a drinking habit in Shandong population. The ALDH2 genotypes and drinking habit were associated with hypertension and lipid profiles especially TC profile in Shandong province. The ALDH2 rs671 genotypes indicated that the gene-related drinking habit and gene variant altogether may affect hypertension and dyslipidemia.

ALDH2 and Cardiovascular Disease

Aldehyde dehydrogenase 2 (ALDH2) is a non-cytochrome P450 mitochondrial aldehyde oxidizing enzyme. It is best known for its role in the metabolism of acetaldehyde, a common metabolite from alcohol drinking. More evidences have been accumulated in recent years to indicate a greater role of ALDH2 in the metabolism of other endogenous and exogenous aldehydes, especially lipid peroxidation-derived reactive aldehyde under oxidative stress. Many cardiovascular diseases are associated with oxidative stress and mitochondria dysfunction. Considering that an estimated 560 million East Asians carry a common ALDH2 deficient variant which causes the well-known alcohol flushing syndrome due to acetaldehyde accumulation, the importance of understanding the role of ALDH2 in these diseases should be highlighted. There are several unfavorable cardiovascular conditions that are associated with ALDH2 deficiency. This chapter reviews the function of ALDH2 in various pathological conditions of the heart in relation to aldehyde toxicity. It also highlights the importance and clinical implications of interaction between ALDH2 deficiency and alcohol drinking on cardiovascular disease among the East Asians.

Genetic variants in ALDH2 predict risk of ischemic stroke in a Chinese population

BACKGROUND AND PURPOSE

Genome-wide association studies discovered a novel correlation between chromosome 12q24 and ischemic stroke in European populations. This study aimed to determine whether two genetic variants (rs10744777 and rs886205) on chromosome 12q24 can modify the risk of ischemic stroke in Chinese population.

METHODS

We recruited 1195 patients with ischemic stroke and 642 healthy Chinese individuals. The rs10744777 and rs886205 polymorphisms in aldehyde dehydrogenase2 (ALDH2) was genotyped and compared using multivariate logistic regression.

RESULTS

The genotype of rs10744777 (CT/TT) was associated with risk of ischemic stroke in males (OR = 1.99, 95% CI = 1.15-3.42, P = 0.013). In contrast, no significant correlation was found in females. Haplotype analysis indicated that haplotype "TA" was associated with increased ischemic stroke risk (OR = 1.85, 95% CI = 1.10-3.12, P = 0.042). Further subtype analysis demonstrated that the rs10744777 (CT/TT) genotype was strongly associated with large artery atherosclerosis subtype in males (OR = 2.27, 95% CI = 1.30-3.95, P = 0.004). After three months follow-up, we found a poorer functional outcome of ischemic stroke associated with the rs886205 GA genotype (OR = 1.76, 95% CI 1.03-3.00, P = 0.057) in males.

CONCLUSIONS

Genetic polymorphisms in ALDH2 modified ischemic stroke risk and outcome in Chinese males, but not in females.

Interactions between ALDH2 rs671 polymorphism and lifestyle behaviors on coronary artery disease risk in a Chinese Han population with dyslipidemia: A guide to targeted heart health management

BACKGROUND

Both aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism and lifestyle behaviors are involved in coronary artery disease (CAD), while the interaction between them is currently unknown.

METHODS

A nested case-control study was conducted in 161 patients with CAD and 495 controls in dyslipidemia population in Yinzhou District, Ningbo, Zhejiang Province, China, in August 2013. Anthropometric data and blood samples were collected, demographic characteristics and lifestyle behaviors information were obtained by a face-to-face interview, dietary intake was assessed by a food frequency questionnaire, and genomic DNA was genotyped.

RESULTS

Carriers with increasing number of A alleles had an elevated CAD risk compared with G allele carriers (adjusted OR = 1.483, 95% CI = 1.114-1.974). Carriers of rs671 A/G and A/A genotypes had a higher CAD risk than carriers of G/G genotype (adjusted OR = 1.492, 95% CI = 1.036-2.148). Similarly, individuals with rs671 A/A genotype had a higher CAD risk than individuals with A/G and G/G genotypes (adjusted OR = 2.161, 95% CI = 1.139-4.101). We found a borderline additive interaction between regular fried food intake and A/A and A/G genotypes, and a significantly additive interaction between sedentary/light physical activity and A/A and A/G genotypes.

CONCLUSIONS

Individuals with A/A or A/G genotypes of rs671 have a higher CAD risk, if they lack physical activity and take fried food regularly, than individuals with G/G genotypes. These findings can help to provide a guide to targeted heart health management.

Associations of common variants at ALDH2 gene and the risk of stroke in patients with coronary artery diseases undergoing percutaneous coronary intervention

Limited data are available about the role of common variants at the aldehyde dehydrogenase 2 gene (ALDH2) on the clinical outcome in Chinese patients with coronary heart disease (CHD) undergoing percutaneous coronary intervention (PCI). In the present study, a total of 1089 patients were consecutively enrolled from January 2012 and July 2013. Six common variants at ALDH2 gene, including rs2339840, rs4648328, rs4767939, rs11066028, rs16941669, and rs671, were selected to test the associations of those polymorphisms with the cardiovascular outcome in patients with CHD after PCI. The clinical endpoints included cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke. The composite of clinical endpoints was defined as the primary endpoint, and every endpoint alone was considered as the secondary endpoints. The median follow-up time was 38.27 months. Our results showed that the common variant rs2339840 was independently associated with a lower risk of stroke in patients with CHD after PCI (codominant model, HR = 0.32, 95% CI, 0.11-0.91, P = .074 for heterozygotes; HR = 0.25, 95% CI, 0.06-1.14, P = .033 for homozygotes; dominant model, HR = 0.32, 95% CI, 0.14-0.74, P = .007). However, no significant associations were found between other 5 single nucleotide polymorphisms (SNPs) and the clinical endpoints. For the first time, the common variant rs2339840 was reported to be a protective factor against stroke in CHD patients with PCI.

The potential of aldehyde dehydrogenase 2 as a therapeutic target in cardiovascular disease

INTRODUCTION

Mitochondrial aldehyde dehydrogenase (ALDH-2) plays a major role in the ethanol detoxification pathway by removing acetaldehyde. Therefore, ALDH-2 inhibitors such as disulfiram represent the first therapeutic targeting of ALDH-2 for alcoholism therapy. Areas covered: Recently, ALDH-2 was identified as an essential bioactivating enzyme of the anti-ischemic organic nitrate nitroglycerin, bringing ALDH-2 again into the focus of clinical interest. Mechanistic studies on the nitroglycerin bioactivation process revealed that during bioconversion of nitroglycerin and in the presence of reactive oxygen and nitrogen species the active site thiols of ALDH-2 are oxidized and the enzyme activity is lost. Thus, ALDH-2 activity represents a useful marker for cardiovascular oxidative stress, a concept, which has been meanwhile supported by a number of animal disease models. Mechanistic studies on the protective role of ALDH-2 in different disease processes identified the detoxification of 4-hydroxynonenal by ALDH-2 as a fundamental process of cardiovascular, cerebral and antioxidant protection. Expert opinion: The most recent therapeutic exploitation of ALDH-2 includes activators of the enzyme such as Alda-1 but also cell-based therapies (ALDH-bright cells) that deserve further clinical characterization in the future.

Genetic polymorphisms in the ALDH2 gene and the risk of ischemic stroke in a Chinese han population

BACKGROUND

Previous studies have shown that aldehyde dehydrogenase 2 (ALDH2) plays a role in ischemic stroke progression. In recent years, the activation of the ALDH2 pathway have been reported serving as a useful index in the identification of stroke-prone participants, and the ALDH2 pathway may be a potential target for the therapeutic intervention in ischemic stroke.

MATERIALS AND METHODS

We evaluated six tagging single-nucleotide polymorphisms (SNPs) of the ALDH2 gene in a case-control study from Hainan of China (488 cases, 503 controls). We used SPSS version 17.0 statistical software, Excel software and other analysis software to explore associations between SNPs and the risk of ischemic stroke various genetic models (additive, dominant, and recessive).

RESULTS

Through statistical analysis, we found that ALDH2 rs886205 [odds ratio (OR) = 6.39; 95% confidence interval (CI) = 1.19-34.38; p = 0.03] and rs7296651 (OR = 9.29; 95% CI = 1.37-63.21; p = 0.02) were associated with increased risk of ischemic stroke in recessive model analysis. In addition, we established that the "AA" genotype (OR = 5.99; 95% CI = 1.11-32.23; p = 0.037) for rs886205 and the "AA" genotype (OR = 8.93; 95% CI = 1.31-60.78; p = 0.025) for rs7296651 were associated with increased ischemic stroke risk.

CONCLUSIONS

Our results provide evidence that variants of ALDH2 gene polymorphisms influence the risk of developing ischemic stroke in Han Chinese population.

Targeting acetaldehyde dehydrogenase 2 (ALDH2) in heart failure-Recent insights and perspectives

Heart failure is one of the major causes of the ever-rising mortality globally. ALDH2 rs671 polymorphism is proven to be closely related to the prevalence of CAD, hypertension, diabetes mellitus and alcoholism, which are etiological factors of heart failure. In addition, growing evidence supports a possible role for ALDH2 in different forms of heart failure. In this mini-review, we will review the recent insights regarding the effects of ALDH2 polymorphism on etiological factors of heart failure and underlying mechanisms involved. In addition, we will also discuss the booming epigenetic information in this field which will greatly improve our understanding of the cardiovascular effect of ALDH2. This article is part of a Special Issue entitled: Genetic and epigenetic control of heart failure edited by Dr. Jun Ren & Yingmei Zhang.